Red azo dye and process of making same.



NTTED STATES PATENT OFFICE.

ADOLF ISRAEL AND RICHARD KOTHE, OF ELBERFELD, GERMANY, ASSIGNORS TO FARBENFABRIKEN OF ELBERFELD (30., OF NEW YORK, N. Y.

RED AZO DYE AND PROCESS OF MAKING SAME.

SPEGIFIGATION forming part of Letters Patent No. 677,517, dated July 2, 1901.

Application filed February 25, 1901- Serial No. 48,740. (Specimens) 2'0 all whorm it m/ag concern:

Be it known that we, ADOLF ISRAEL and RICHARD KOTHE,dOCtO1S of philosophy,chernists, (assignors to the FARBENFABRIKEN OF 5 ELBERFELD COMPANY, of New York,) residing at Elberfeld, Germany, have invented a newand useful Improvement in newAzo Dyes; and we hereby declare the following to be a clear and exact description of our invention.

In two applications for Letters Patent filed February 20, 1901, and bearing Serial Nos. 48,167 and 48,168, we have described the production of new, simple, and mixed guanidin derivatives of amidonaphthol sulfonic acids having the following general formula:

0 in which formula R means a hydrogen atom which can be replaced by a fatty or an aromatic radical, such as methyl, phenyl, oxynaphthyl, oxynaphthyl-sulfonic acid, or the like.

5 Our present invention relates to the production of valuable new azo coloring-matters by causing two molecules of either the same or two different diazo compounds to act on the said guanidin derivatives.

We point out specifically that by the term diazo compound in the following specification we intend to denote a simple diazo compound as well as a diazotized amidoazo compound, such as diazoazobenzene, diazoazotoluene, or the like.

The new dyestuffs are alkaline salts of acids having the following general formula:

in which formula R means a hydrogen atom which can be replaced by a fatty or an aromatic radical, N:NX and N=N-X, meaning either the same ortwo different radicals of diazo compounds, and which are from reddish-brown to dark-brown powders having a metallic luster, dissolving in water with from orange to bluish-red color. They dye unmordanted cotton from orange to blu- 5o ish-red shades which are of a remarkable fastne ss to acids and to light.

In carrying out our new process practically we can proceed as follows, the parts being by weight: 24.2 parts of paraxylidin are diazotized in the usual manner with the aid of 78.4 parts of hydrochloric acid (of 15 Baum) and fourteen parts of sodium nitrite. The resulting diazo solution is then slowly stirred into a solution prepared from 50.3 parts of dioxydinaphthyl guanidin disulfonic acid (prepared from the thio-urea compound of beta amido alpha -naphthol beta,-sulfonic acid) having the formula:

and one hundred and twelve parts of sodium carbonate,(Na OO After havingstirred for several hours the formation of the dyestuff will be finished. The latter is separated from the mixture by the addition of common salt and isolated by filtration. The new coloring-matter thus obtained is the sodium salt of an 30 acid having most probably the formula:

The new coloring-matter dyes unmordanted cotton red shades which are fast to acids and and to light.

The process proceeds in an analogous manner if instead of the (Haze compound mentioned in the example other diazo compounds are employed. On using, for instance, one. molecule of diazotized anilin and one molecule of diazotize-d para-amidoacetanilid a red dyestu'fif and on using two molecules of alphanaphthylamin a bluish red dyestuff is obtained.

Having now described our invention and in what manner the same is to be performed,

what We claim as new, and desire to secure by Letters Patent, is

1. The process for producing new azo dyestuffs which process consists in first combine ing two molecules of diazorcompounds with one molecule of a gu'anidin derivative having in a free state the herein-defined general formula:

- secondly precipitating the resulting'dye'stufis by means of asuitable salt and finally isolating the same from the reaction mixture, substantially as hereinbefore described.

2. The process for producing a new disazo bining two molecules of diaz otized para-xylidin With one molecule of thedioxydinaphthyl-guanidin disulfonicacid having in a free state the formula:

with the aid of a suitable salt, and finally isolating the same from the reaction migrate,

substantially as hereinbefore described.

3. The herein described new azo dyestuffs which are alkaline saltsof acids having the hereinbefore-defined general formulai and which are from reddish-brown to darkbrown powders having a metallic luster, dissolving in water with from orange to bluishred color, dyeing unmordanted cotton from orange to bluish-red shades which are of a remarkable fastness' to acids and to light, substantially as hereinbefore described.

4:. The herein-described new disazo dyestuff being an alkaline salt ofan acid having most probably the following formula:

which in the shape of the sodium salt is a recldish-brown powder having a metallic luster, soluble in Water with ared color, insoluble in concentrated hydrochloric acid and being dissolved by concentrated sulfuric acid of 66 Banm with a bluish-red color which is not changed by the addition of a small quantity of ice, while on the addition of a larger quantity of ice the dyestufi is precipitated in the shape of reddish-brown flakes, dyeing uninord anted cotton red shades of a remarkable fastness to acids and to light,-snbstantial1yas hereinbefore described. v In testimony whereof we have signed our names in the presence of two subscribingwit OTTO KoNic, EMIL BLOMBERG.

secondly precipitating the resulting dyestn'if dyestufi which process consists in first com- 

